The FBI executed search warrants at the home and office of a businessman whose partnership with the agency that runs school buses in Dallas lost millions of dollars of taxpayer money.

A federal judge sealed the search warrants. But NBC 5 Investigates confirmed federal agents raided a high-rise office in downtown Dallas and a luxury home in a New Orleans suburb on June 26.

The home belongs to Robert Leonard, the chief executive of Force Multiplier Solutions; the downtown location was the company's Dallas office on the 49th floor of Chase Tower. Force Multiplier is the company Dallas County Schools partnered with on a deal for school-bus cameras that put the agency near financial ruin.

Former U.S. Attorney Matt Orwig said a search warrant is a significant development in a criminal case. The Federal Bureau of Investigation was probably searching for financial records to see if there were any improper dealings between officials of the business and the bus agency, he said.

The FBI will not discuss the nature of the investigation, but did acknowledge that agents served warrants at the Dallas high-rise and the home in Louisiana on the same day in June.

Leonard has been cooperating with federal agents in the investigation, his lawyer, Chris Lewis, said in a statement.

"It is my understanding that the FBI has been engaged in a lengthy investigation to determine whether there was any criminal misconduct on the part of any person or persons, with respect to the business relationship between Force Multiplier" and the bus agency, Lewis said. "During this extremely stressful process, Mr. Leonard has been completely cooperative with the authorities and has done nothing to impede or complicate the FBI's investigation."

Last week, NBC 5 Investigates reported that the former superintendent of the bus agency, Rick Sorrells, and his family had a personal relationship with Leonard. The two men rented adjacent apartments in the French Quarter where Sorrells vacationed. Despite the close proximity, Sorrells denied Leonard played a role in him getting the apartment.

Sorrells remains on the payroll at the bus agency until December under terms of a retirement deal reached with the board earlier this year, when he was forced out amid questions about the agency's financial troubles. Following the report on the New Orleans apartment, the president of the bus agency's board, Gloria Levario, said she intends to revisit Sorrell's retirement package.

Voters will decide Nov. 7 whether the bus agency remains in business or is abolished, with its assets distributed to school districts so they could run their own bus services.